Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 359 PM EDT Tue Aug 22 2017 Valid 00Z Wed Aug 23 2017 - 00Z Fri Aug 25 2017 ...Enhanced risk of severe weather and slight risk of flash flooding expected along a cold front... ...Showers and thunderstorms will continue across the Southern Rockies... A cold front across the eastern to southern U.S. will be the main weather causer over the next couple of days for much of the U.S. On Tuesday evening and night, the cold front will stretch from the Lower Great Lakes through the Ohio Valley, Tennessee Valley, Lower Mississippi Valley, and Southern Plains. Along and ahead of this front, showers and thunderstorms will be likely. Areas from the Ohio Valley toward the Lower Great Lakes and Northeast are under a slight to enhanced risk of severe weather--see the Storm Prediction Center for more information on the severe weather threat. Additionally, plenty of available moisture will lead to a slight risk of flash flooding in these areas on Tuesday night, as well as for portions of the Southern Plains and into Arkansas. As the cold front progresses, by Wednesday, showers and thunderstorms will be possible from the Mid-Atlantic south and west into the Tennessee Valley, Southeast, Lower Mississippi Valley, and Southern Plains. On Wednesday the threat for flash flooding will shift into the Carolinas, and a few storms could be strong there as well. Scattered thunderstorms are expected to continue for the Carolinas, Gulf Coast, and Southern Plains on Thursday. This cold front will lower temperatures for most of the U.S. east of the Rockies, and some areas could see temperatures 10 or so degrees below average. For the Southern Rockies, sufficient moisture and an upper-level trough to the west will lead to scattered thunderstorms on Wednesday. Some storms could cause flash flooding, so there is a slight risk of excessive rainfall in effect for Wednesday and Wednesday night for portions of New Mexico and far western Texas. Some storms could contain heavy rainfall northward into the Central Rockies and Central High Plains as well. Farther north, thunderstorms are expected for the Central Great Basin on Tuesday evening. By Wednesday afternoon, a cold front will approach the Great Basin, leading to more showers and thunderstorms there on Wednesday evening and into Thursday. After above normal temperatures for the Northern Great Basin and Northern Rockies on Tuesday and Wednesday, slightly below normal temperatures are expected for Thursday. Tate Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php